I've been having trouble getting my lg4 engine running right. I decided to look at the map sensor. Upon inspection I noticed it didn't have a vacuum hose running to it. I tried looking at the under-hood vacuum diagram and didn't see anything about the map sensor. I see on the vacuum diagram it talks about a vacuum sensor. That isn't the same things as the map sensor is it?

I tried following where the vacuum hose for the "vacuum sensor" goes, but it goes behind the distributor and into a wire loom. I think it may be the same hose coming out of another harness on the passenger side of the vehicle by the firewall, but then it travels across the firewall and into a "t" over on the driver's side with a bigger vacuum hose coming from the nipple on the intake manifold. This line then goes into another loom behind the brake booster. Is the small vacuum hose off the back of the carb supposed to go to the map sensor or does it follow the route I just explained? I'm somewhat confused and just want to know which hose is supposed to go to the map sensor and where to find it.

 

Anyone have any ideas?

 

MAP sensor = "vacuum sensor"

There's no "T" in the one that goes to that. Its correct vac port is the little one on the back pass side of the carb.

The line with the "T" feeds the cruise control and the HVAC ssytem... in other words, accessories. Things that aren't part of "the engine" at all, and therefore aren't on the vac line diag for "the engine".

The sensor itself is on a bracket between the brake booster and the fender, right above the huge connector for the wiring between the pass compartment and the engine room.

 

Thanks for the reply. Someone else pointed out that my car has a vac and baro sensor, so the sensor I was looking at was the baro which isn't supposed to have a vacuum line to it. That clears it up a lot, but thanks again for your help.

 

I've been trying to find where the missing vacuum hose goes from my 1984 Z28 's barometric sensor. It looks like you found out that there isn't one attached? Is that the absolute solution? Does it need to be capped off? Thanks you for your time.

 

Ya, someone pointed out to me that these cars have a manifold vacuum sensor and a baro sensor unlike most cars I'm used to that just have a MAP sensor. The baro sensor is the one on the passenger side of the car. The two sensors look identical. The baro sensor just reads the atmospheric pressure so that's why it doesn't have a vacuum line to it. Don't cap it off either or else the sensor will give a false reading. It sounds like your baro sensor is set up correctly the way it is. Hopefully that clears everything up for you.